When movie productions are to be distributed, a great difficulty is posed by language differences. In order to set aside time for producing audio dubbing and subtitles, the movie industry has adopted a business method by which optical discs are distributed in the U.S.A. first, and distribution timing of optical discs in non-English regions is staggered, for example for Western Europe and Japan, and for Eastern Europe and other Asian countries. (This business method is called “time-shift”.) With the use of this time-shift method, movie productions are distributed to each of different regions in the world, with English audio and/or subtitles and the audio and/or subtitles in the native language of the region. It should be noted the Patent Document 1 mentioned below discloses an example of the prior art related to techniques for playing back audio and playing back sub-images on DVDs.
There are users, not so large in number but definitely in any country and region, who desire to own an optical disc in a version that is not distributed in his/her own country or region. A typical example is that there are some users who purchase a translated version of an optical disc in their second language besides English and their native language in order to learn the second language. Inmost cases, however, the places where such discs on which a movie production is recorded in a second language are sold are limited to the areas where the language is spoken, and it is difficult for most users to purchase such a disc in his/her own country. In addition, even if a user orders such a disc from the area where the language is spoken, the user may not be able to play back the disc on the playback apparatus he/she owns, due to the region code restriction.
The second languages users wish to learn are, for example, Japanese, German, French, Chinese, Russian, and there is a wide range in variation of languages for different users. It is a large burden on distributors to keep the lineup of products so as to cover all different languages. It is also an extremely high marketing risk for distributors to bring products in only certain languages into markets. Using discs for learning languages is a mere example, and there are some users in any country for sure who wish to have a disc in a version that is not distributed in their own country. Conventionally, there is no technique that makes it possible for distributors to meet such demand of the users.    Patent Document 1    Japanese Patent No. 2,821,030